In the related art, when a smart card communicates with an electronic device (e.g., a radio frequency (RF) read/write device supporting a carrier frequency of 13.56 MHz, such as a near field communication (NEC) RE read write device), the distance between the smart card and the electronic device is so small that the smart card can be in an electromagnetic field of the electronic device, and can acquire energy from the electromagnetic field of the electronic device. In the related art, when the smart card enters the field (i.e., the smart card enters the electromagnetic field of the electronic device to acquire energy), the smart card needs to interact with the electronic device so that the smart card can be changed from an power-off state to an active state via an idle state, after the smart card leaves the field (i.e., the smart card is far away from the electromagnetic field of the electronic device), the smart card changes from the active state to the power-off state. When the smart card needs to perform subsequent operations to re-enter the field, the smart card needs to interact with the electronic device again so that the smart card can be changed from the power-off state to the active state via the idle state, to perform subsequent operation. However, the communication process between the smart card and the electronic device is complicated when the smart card re-enters the field, it is required to interact with the electronic device to change the state again, which takes much time and efficiency is low.